Electrical condenser and spacing strip therefor



Jan. 11, 1938. A. D] GIACOMO 2,104,797

ELECTRICAL CONDENSER AND SPACING STRIP THEREFOR File d Feb. 15, 1935 I I V l' {l INVENTOR, Am'allo D13 fijaeomo,

BY z

A RNEY.

Patented Jan. 11, 1938 UNITED STATES ELECTRICAL CONDENSER. AND SPACING s'mlr THEREFOR Aniello Di Giacomo, New York, N. Y., assignor to Condenser Corporation of America, Jersey City, N. J., a corporation of New York Application February 15, 1935, Serial No. 6,687

8 Claims.

My present invention relates generally to electrical apparatus, and has particular reference to condensers or cells of the type in which electrodes are arranged in spaced relation.

While my invention is primarily directed toward the improvement of electrolytic cells or condensers of the so-called dry type, nevertheless it will be understood that many phases of'the invention are not restricted to a specific application of this character.

It is a general object of the invention to provide an improved type of spacing medium for the purpose of separating the electrodes and accommodating a suitable impregnating substance. In the case of an electrolytic cell, the spacing medium serves to separate two metallic foils which constitute electrodes, at least one of the foils being provided with an electrolytically deposited film, and the spacing medium serves further to carry and accommodate an electrolyte that is usually in pasty, viscous, or semi-solid form. I

It has been customary practice, in electrolytic cells, and also in other apparatus of the same generic character, to employ an open-work fabric or gauze as the spacing medium. For various reasons, it would be desirable if gauze could be dispensed with. It is relatively expensive; it is necessarily thicker than other substances, such as paper; and it usually carries certain impurities which may unfavorably affect the characteristics of the resultant device. From a number of aspects, paper is preferable to gauze. In fact, in condensers of the so-called paper dielectric type, it has become regular practice to employ thin, pure paper.

The use of paper alone, in an electrolytic cell, has proven to be unfeasible because of there quirement, in such cells, that the electrolytically deposited film be maintained in constant and adequate contact with a suitable electrolyte. While the paper, by virtue of its inherent porosity, is capable of .carrying, in impregnation, a certain quantity of the electrolyte, nevertheless it has'been found that insufilcient quantities of the electrolyte are in maintained contact with the film. When an electrolytic cell body employing paper is unwound, it is found that large areas of the filmed foil are entirely devoid of any contact with the electrolyte.

It is a more specific object of my invention to provide a spacing medium in the form of paper, whereby the advantages of paper, as distinguished from gauze, are achieved without the corresponding disadvantages heretofore encountered. My invention is predicated upon the discovery that a strip of paper when suitably crimped or crinkled, partakes in a remarkable manner of the qualities that, are usually found in gauze. It is my theory that the crimping produces a multiplicity of pockets in direct contact with the foil, and that these pockets serve as a highly eiiicient fneans for accommodating relatively large masses of electrolyte in firm and maintained contact with the foil.

From one aspect, my invention does not require the crimping of the paper, inasmuch as the pockets I have alluded to may, under certain circumstances, be formed by crimping one or both of the foils serving as electrodes. I

It is a particular feature of my invention to provide a. crimped paper spacer in which the grain of the crimping runs in a substantially transverse direction. This greatly facilitates the proper impregnation of a wound body, where the introduction of the electrolyte into the body is carried out after the winding procedure.

The term crimping, and similar terms, as, used herein and in the appended claims, are not intended to refer to any marked or regular undulations such as those found in corrugated board or the like; but is intended to refer, rather, to a sort of irregular crinkling or sinuosity more of the character that is found in certain paper napkins, or the paper or other material that is often referred to as being "craped. With crimping of such character, the individual pockets produced thereby in the spacer extend transversely of the length of the spacer for a. distance substantially less than the width of the spacer.

I achieve the foregoing objects, and such other objects as may hereinafter appear or be pointed out, in the manner illustratively exemplified in the accompanying drawing, wherein- Figure l is a perspective view, on an exaggerated scale, showing the elements entering into an electrolytic cell constructed in accordance with the present invention;

Figure 2 is a greatly enlarged, fragmentary, cross-sectional view through five superposed plies of a body wound as in Figure 1, this view being taken substantially in the direction 22 of Figure 1; and

Figure 3 is a fragmentary plan view of a piece of the present improved spacer.

For the purpose of illustrating the general nature of my invention, I have chosen to depict an electrolytic cell or condenser of the so-called dry type, in which a pair of metallic foil strips I0 and Il are interwound into a rolled body I2.

At least one of these strips is preliminarily coated with an electrolytically deposited film which, where the device is used as a condenser, constitutes the dielectric of the condenser. In the illustrated embodiment, the foil I is so coated; and in Figure 2 the film is designated by the reference numerals l3. The foils are preferably of aluminum or similar filmable material, and in the illustrated device the foil II is uncoated and serves as the cathode of the cell in question.

On each side of one of the electrodes a spacer strip is provided, and these strips H and i5 are interwound with the foil strips during the winding procedure. It will be understood that there may be more than one such spacing strip between the superposed foils; and it will be further understood that the strips ll and I5 are usually and preferably of slightly greater width than the foil strips, so that in the wound body the foil strips are completely enclosed. Tabs l6 and II are usually caused to project from the opposite ends of the body l2 for the purpose of establishing the necessary electrical connections with the foil strips i0 and II, respectively.

In accordance with my invention, each of the spacing strips i4 and I5 comprises a length of crimped paper of the character shown in Figure 3. The method of crimping the paper forms no essential part of the present invention, although I may point out that one convenient way of accomplishing the object is to pass an ordinary thin paper strip through a set of suitably configured rollers.

The crimping produces a slightly increased overall thickness of the resultant paper, and the crimping is purposely provided with its grain running in a substantially transverse direction, as shown in Figure 3.

In the resultant wound body, a multiplicity of pockets or recesses l8 are provided, as shown most clearly in the exaggerated cross-section of Figure 2; and the impregnating medium, whatever character it may be, is accommodated not only within the fibers of the paper, but also on its opposite surfaces, filling in all of these voids or pockets. In the case of an electrolytic cell, the impregnating medium is a pasty or viscous electrolyte, and its accommodation within the pockets i8 serves to maintain a substantial quantity thereof in constant and assured contact with the contiguous surfaces of the electrodes, especially with the films I 3. The result is that the life of the resultant cell is materially increased.

The application of the impregnating medium, such as the electrolyte, may be effected in a variety of ways. In one procedure foil and paper strips are cut to length in advance, and the paper strips are smeared with the electrolyte before the interwinding is carried out. Another and preferred mode of procedure lies in interwinding the strips by means of a winding machine or the like, the foil and paper strips being drawn from supply reels and fed onto suitable mandrels or arbors. In this procedure, the wound bodies are thereafter immersed into a bath of the electrolyte to permit the latter to work its way by capillary action into the fibers of the paper and into the pockets l8. By running the grain of the crimping in a substantially transverse direction, the latter procedure is facilitated, since the electrolyte finds its way more readily into the interior of the wound body.

I have not illustrated a construction in which the foil is crimped, but it will be readily understood that in so far as the provision of pockets is concerned, this may be accomplished by crimping one or both foils, either with or without the corresponding crimping of the paper spacing strips.

It will also be understood that the invention is, from a number of aspects, not restricted to dry electrolytic cells or condensers, but may find a wider applicability in electrical devices in general, wherein a spacing medium of porous and impregnatable character is intended to be interposed between conductive strips serving as electrodes or the like.

In general, it will be understood that changes in the details, herein described and illustrated for the purpose of explaining the nature of my invention, may be made by those skilled in the art without departing from the spirit and scope of the invention as expressed in the appended claims. It is, therefore, intended that these details be interpreted as illustrative, and not in a limiting sense.

Having thus described my invention, and illustrated its use, what I claim as new and desire to secure by Letters Patent is 1. In a. condenser, a pair of metallic foils serving as electrodes, and a spacer between them comprising crimped paper, the pockets produced in said spacer by the crimping thereof being substantially parallel, and of lengths substantially less than the over-all dimension of the crimp 01' said spacer as measured parallel to said pockets.

2. In a condenser, a pair of metallic foils serving as electrodes, a spacer between them comprising crimped paper, the pockets produced in said spacer by the crimping thereof being substantially parallel, and of lengths substantially less than the over-all dimension of the crimp of said spacer as measured parallel to saidpockets, and an impregnating medium carried within and upon said paper and filling in said pockets.

3. In an electrolytic cell, a pair of electrodes, at least one of which is of film forming metal, and a crimped paper spacer therebetween impregnated with an electrolyte, the pockets produced in said spacer by the crimping thereof being substantially parallel, and of lengths substantially less than the over-all dimension of the crimp of said spacer as measured parallel to said pockets.

4. In an electrolyte cell, a pair of metallic foils serving as electrodes, at least one of which foils is of film forming material, a spacer between them comprising crimped paper, the pockets produced in said spacer by the crimping thereof being substantially parallel, and of lengths substantially less than the over-all dimension of the crimp of said spacer as measured parallel to said pockets, and an electrolyte carried within and upon said paper and filling in said pockets.

5. In a condenser, a pair of metallic foil strips interwound into rolled form and serving as electrodes, and a spacer on each side of one of them comprising a strip of crimped paper, the grain of said crimping running in a direction substantially transverse to the length of said spacer strip, with the individual pockets produced therein by the crimping thereof being substantially less than the width of said spacer strip.

6. In an eletrolytic cell, a pair of electrodes comprising foil strips at least one of which is electrolytically coated with a film, a spacing strip on each side of one of said electrodes, said strips being interwound to form a rolled body, the spacing strips comprising crimped paper, the

grain of said crimping rumiing in a direction substantially transverse to the lengths of said spacmension of the crimp of said spacer as measured ing strips, with the individual pockets produced parallel to said pockets.

therein by the crimping thereof being substan- 8. As a new article of manufacture, a. spacer tially less than the width of said spacing strips. for separating the electrodes of a condenser,

5 and an electrolyte carried by said spacing strips. comprising a strip of crimped paper, the grain of 7. As a new article of manufacture, a. spacer said crimping running in a direction substantially for separating the electrodes of an electrolytic transverse to the length of said spacer strip,

condenser, comprising crimped paper in which with the individual pockets produced therein by the pockets produced in said spacer by the crimpthe crimping thereof being substantially less than 10 ing thereof are substantially parallel and of the width of said spacer strip. 10

lengths substantially less than the over-all di- ANIEILO DI GIACOMO. 

